自升式平台桩腿相位差的敏感性分析

Sensitivity Analysis of Leg RPD of Jack-up Platform

为掌握自升式平台桁架式桩腿相邻弦杆间相位差(RPD)的计算方法,得到影响RPD值的主要参数,基于刚度和屈曲分析理论,以122 m自升式平台桁架式桩腿为例,对相邻弦杆间的RPD值及敏感性进行分析。分析结果表明:基于刚度理论的RPD求解方法简单,能较好地解决有限元模拟的变形协调问题;上、下导向的水平刚度和升降系统的垂向刚度是影响桩腿RPD的主要因素,通过对刚度的敏感性分析,敏感度最大的影响因素是下导向的水平刚度,且桩腿的相位差随水平刚度和垂向刚度的增加而显著降低;可在设计阶段对敏感度较大的因素加以控制,设计和改变平台的容许RPD值,从而保证既满足桩腿结构安全,又避免RPD设置不合理带来的频繁启停。研究结果可为平台升降操作的监测和报警提供计算依据,对工程实际具有指导意义。

In order to master the calculation method for the rack phase difference( RPD) between adjacent chord of jack-up platform truss-type leg,and obtain the main influence parameters of RPD,based on the theory of rigidity and buckling analysis,by taking the 122 m water-depth jack-up platform truss-type leg as case study,the RPD and sensitivity between the adjacent chord of truss-type leg have been analyzed. The result shows that the RPD method based on the rigidity theory is very simple and can solve the finite element simulation of deformation compatibility. The main factors affecting the leg RPD are the horizontal stiffness of the guide and the vertical stiffness of the jacking system. Through sensitivity analysis of stiffness,the most sensitive influential factor is the lower guide horizontal stiffness. The leg RPD is significantly reduced with the increase of horizontal stiffness and vertical stiffness. Controlling the more sensitive factors at the design stage could be done to design and change the allowable RPD value of the platform,so as to ensure the safety of the legs structure and avoid frequent start and stop caused by unreasonable RPD set. The proposed method could provide the basis for monitoring and alarming of the actual jacking operation of the platform,presenting guiding significance to the actual project.